(1) Field of the Invention
The present invention pertains to a light transmitting apparatus that is employed primarily in ophthalmic surgery. The apparatus is comprised of an optic fiber having a flexible length with a light source connector mounted on one end of the optic fiber. The opposite end of the optic fiber is adapted to be mounted on an ophthalmic surgery instrument to serve as a source of illumination for the instrument. The cross-sectional area of the optic fiber transitions as it extends from its proximal end to its distal end, with the cross-sectional area adjacent the optic fiber proximal end being larger than the cross-sectional area adjacent the optic fiber distal end. The changes in the cross-sectional area of the optic fiber along its length enable the optic fiber to transmit a greater amount of light from its proximal end to its distal end than was previously possible with prior art light transmitting optic fibers having a constant cross-sectional area along their lengths.
(2) Description of the Related Art
In a typical ophthalmic surgery procedure, it is necessary that a light source be provided inside the patient's eye so that the surgical site in the interior of the eye is well illuminated, enabling the surgeon to easily view the surgical site through an endoscope. Most common ophthalmic surgery procedures involve first making a small incision in the eye for insertion of an illuminator. A second incision is made in the eye for insertion of the instrument to be used by the surgeon in performing the surgery. Alternatively, when using an instrument that is provided with its own light source, only a single incision is made in the eye for insertion of the illuminated instrument into the interior of the eye. To minimize the invasiveness of this type of surgery, it is desirable to reduce the size of the incisions. This is accomplished by reducing the sizes of the light source or illuminated instruments inserted through the incisions.
There are various different types of illumination devices employed in ophthalmic surgery. These include illumination cannulas that are inserted through an incision in the eye and secured to the exterior surface of the eye. One or more optic fibers extends through the cannula. The proximal end of each optic fiber is typically secured to a connector that connects to a light source. The distal end of each optic fiber is positioned in the cannula where, when the connector is connected to the light source, light transmitted through the optic fiber is emitted from the distal end of the optic fiber illuminating the interior of the eye. An example of this type of illumination device is disclosed in U.S. Pat. No. 5,425,730.
Other types of illumination devices are incorporated into microsurgical instruments employed in ophthalmic surgery. These types of illumination devices also typically employ one or more optic fibers having flexible lengths with opposite proximal and distal ends. The proximal end of each fiber is again secured to a connector that connects the fiber proximal end to a light source. The distal end of each fiber is adapted to be mounted to an ophthalmic surgery instrument, for example a pick or blade, a scissors or a forceps. Connecting the connector to a light source transmits light through the optic fiber to the optic fiber distal end providing illumination to the area of the working end of the ophthalmic surgery instrument. Examples of these types of instruments are disclosed in U.S. Pat. Nos. 5,785,645 and 5,807,242.
The miniaturization of ophthalmic surgery instruments that provide illumination to a surgical site in the eye has resulted in a reduction in the size of the instrument's optic fiber which has resulted in a reduction in the capability of the optic fiber to introduce enough light to the surgical site for effective visualization by the surgeon. As explained above, the typical illuminated ophthalmic surgery instrument employs at least one optic fiber having a flexible length with opposite proximal and distal ends. The proximal end of the fiber is attached to a light source connector and the distal end of the fiber is attached to an ophthalmic surgery instrument or is adapted to be attached to an instrument. The typical optic fiber employed with ophthalmic surgery instruments has a diameter of 0.75 mm. Reducing the size of the ophthalmic surgery instrument to enable a reduction in the size of the incision in the eye requires a corresponding reduction in the diameter of the optic fiber of the instrument. However, the amount of illumination that can be transmitted by an optic fiber is fundamentally dependent on the cross-sectional area of the optic fiber. A reduction in the cross-sectional area of the optic fiber reduces its ability to transmit illuminating light to the surgical site. Therefore, there is a need for a light transmitting apparatus employed with ophthalmic surgery instruments that has a reduced size, enabling a reduction in the size of an incision into the eye and a reduction in the invasiveness of ophthalmic surgery, while still transmitting sufficient light to the interior of the eye for effective illumination and visualization of the surgical site by the surgeon.